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package java.util.function;

import java.util.Objects;


Represents a function that accepts two arguments and produces a result. This is the two-arity specialization of Function. 
This is a functional interface whose functional method is apply(Object, Object). 
Type parameters:
  • <T> – the type of the first argument to the function
  • <U> – the type of the second argument to the function
  • <R> – the type of the result of the function
See Also:
Since:1.8
/**
 * Represents a function that accepts two arguments and produces a result.
 * This is the two-arity specialization of {@link Function}.
 *
 * <p>This is a <a href="package-summary.html">functional interface</a>
 * whose functional method is {@link #apply(Object, Object)}.
 *
 * @param <T> the type of the first argument to the function
 * @param <U> the type of the second argument to the function
 * @param <R> the type of the result of the function
 *
 * @see Function
 * @since 1.8
 */
@FunctionalInterface
public interface BiFunction<T, U, R> {

    
Applies this function to the given arguments.

Params:
  • t – the first function argument
  • u – the second function argument
Returns:the function result
/**
     * Applies this function to the given arguments.
     *
     * @param t the first function argument
     * @param u the second function argument
     * @return the function result
     */
    R apply(T t, U u);

    
Returns a composed function that first applies this function to its input, and then applies the after function to the result. If evaluation of either function throws an exception, it is relayed to the caller of the composed function. 
Params:
  • after – the function to apply after this function is applied
Type parameters:
  • <V> – the type of output of the after function, and of the composed function
Throws:
Returns:a composed function that first applies this function and then applies the after function
/**
     * Returns a composed function that first applies this function to
     * its input, and then applies the {@code after} function to the result.
     * If evaluation of either function throws an exception, it is relayed to
     * the caller of the composed function.
     *
     * @param <V> the type of output of the {@code after} function, and of the
     *           composed function
     * @param after the function to apply after this function is applied
     * @return a composed function that first applies this function and then
     * applies the {@code after} function
     * @throws NullPointerException if after is null
     */
    default <V> BiFunction<T, U, V> andThen(Function<? super R, ? extends V> after) {
        Objects.requireNonNull(after);
        return (T t, U u) -> after.apply(apply(t, u));
    }
}